A138817 - OEIS

%I #5 Mar 11 2014 01:34:11

%S 326,748,166,748,166,166,748,748,166,166,748,748,166,748,748,748,166,

%T 166,166,748,166,166,166,166,166,166,166,748,748,166,748,748,166,748,

%U 166,166,166,166,166

%N Concatenation of final digit of n-th Mersenne prime A000668(n), final digit of n-th even superperfect number A061652(n) and final digit of n-th perfect number A000396(n).

%C Also, concatenation of final digit of n-th Mersenne prime A000668(n), final digit of n-th superperfect number A019279(n) and final digit of n-th perfect number A000396(n), if there are no odd superperfect numbers.

%C Also, concatenation of n-th term of A080172, A138125(n) and A094540(n).

%C a(1)=326. For n>1 a(n) is equal to 166 or 748, only.

%H L. C. Noll, <a href="http://www.isthe.com/chongo/tech/math/prime/mersenne.html">Mersenne Prime Digits and Names</a>.

%H Omar E. Pol, <a href="http://www.polprimos.com">Determinacion geometrica de los numeros primos y perfectos</a>.

%Y Cf. A000396, A000668, A019279, A061652, A080172, A094540, A138125, A138817.

%K base,nonn,less

%O 1,1

%A _Omar E. Pol_, Apr 01 2008